Summary

A big yellow fever outbreak in Angola has depleted the world's emergency vaccine stockpile and raised worries that future outbreaks of the mosquito-borne virus could be impossible to control. The Angolan outbreak has caused 490 confirmed cases and 198 deaths so far, but experts say the real toll may be 10 times as high. A vaccination campaign has already reached 6 million people in Luanda, where the outbreak began, but the disease has spread to other provinces as well and the vaccine is running out. Only four facilities in the world produce yellow fever vaccine, and their production methods are antiquated and difficult to scale up. Additional outbreaks in other African cities, or in Asia, where yellow fever has never gained a foothold, could be catastrophic, experts say.